User or account management is a must-have feature in business applications. For examples, one device should be used by many employees and the employees have different roles in the project. The apps must be able to authenticate user, authorize them and let them access the resources corresponding to their roles. We can manage all these things in app databases within our own tables or we can use AccountManager providing access to a centralized registry of the user’s online accounts. With AccountManager, the user enters credentials (username and password) once per account, granting applications access to online resources with “one-click” approval. In this blog post, I would like to make a small demo how we can integrate ASP.NET Identity service for authenticating user with AccountManager. I’ll only focus on addAccount part, the other functions will be discussed in other posts if necessary.
Following the post C# – ASP.NET Web API and ASP.NET Identity, I would like to show how we can consume a REST web service authenticated by ASP.NET Identity within Android. In this post, we’ll repeat the steps we’ve done before in .NET client but now with Java and Android. If you follow my posts before in Android section, you must be very familiar with consuming ASP.NET Web API service. We’ll use same technique again, no big deal. However, I’ll introduce some new functions in JSONHttpClient class for communication with ASP.NET Identity.
Handling asynchronously is a ‘must’ for all mobile applications when executing any long time operation. For example, in Android, when a network operation is going to be called, it has to be executed on other thread (not UI thread). If the developers try to run a network operation on UI thread, Android OS will force the app to stop with an exception of android.os.NetworkOnMainThreadException. As usual, the developers will put long time operation in a AsyncTask (or a Thread) and let it run. I also introduced this class in many Android posts before. However I have only one AsyncTask running at a time in all of examples. A reader asked me if I can create a list of AsyncTask and execute them at the same time. Something likes Parallel Computing? The answer is ‘Yes, of course’. We can do that in Android. Therefore, in this post, I would like to show how I simulate a multi-threading case with AsyncTask and some experimental cases for comparison between native Java and Android Java in Parallel Computing
Publishing core data through web service is always a work-intensive progress because we have to build up a web server, define service interface, make data access layer and implement user management. It has never been easy and always requires advanced knowledge. The resources of developers have to be distributed not only for client but also for server. Therefore the cost gets more. Moreover because of strong growth in market of smartphone and table running on different operating systems, the developers are put into a challenge to make a universal web service which can be easily consumed in all platforms. In my previous posts, such as How to call ASP.Net Web API service from Android? or Android – Media player and ASP.NET Web Api, we are able to build up a universal REST web service which can be consumed in all platforms supporting HTTP protocols.
I think, as developers, all of us want to write less code but still keep the code structure clean and clear as possible. When I develop app in Android, I always miss MVVM (WPF in Visual Studio) where I can bind control to event easily. Android makes me ‘bored’ when I have to look up each control with findViewById() and then initialize them so that I can use them later. Even though that the problem with findViewById() can be solved with Roboguice, but I still have to write the code for registering event such as click, long click,… It’s really boring and I want to have less code for that task. I need something ‘clean and clear’. Therefore in this post, I would like to introduce AndroidAnnotations, a framework for helping us keeping our code thin and healthy.
Bugs are always the most annoyed things for developer. It’s a dream (which never comes true) that a software runs without any problem at client’s site. There are always some points that developers have to improve after deployment. The more time developers invest for testing, the better the software is and the less annoyance developers have. I made many examples of Android development which are small apps and illustrate how a point of interest works. As a demo, I didn’t care too much about if there is a bug in app code because it isn’t a complete application. However if we want to make something that can be sold to customers, we have to be sure that our software should be reliable as it could be. Therefore in this post I would like to discuss some simple basic tests in Android development. We will learn how to write a logical unit test with JUnit, an integration unit test with test classes from Android and some advanced test cases with Roboguice, Robolectric and Mockito.
If you follow my previous posts, you may already know that we discussed how to make an application with database in Android before in Android, Dependency Injection (IOC) with roboguice and MVVM (Model-View-ViewModel) pattern. Although the main topic in that article relates to Dependency Injection but we had also a working example which fully supports all CRUD actions for Sqlite database. However, in practice, it shouldn’t work like that because the synchronous read/write actions will block the user interface and your apps will freeze. When your database grows over time, the query time gets longer and you app will completely freeze during the query get executed. Therefore, in this post, I would like to make a sample for illustrating how a database application can work in asynchronous mode.
Android emulator is very famous for its performance. It’s very, very, very notoriously… slow. If you debug your app with Android emulator, it get more extremely slower. This performance problem stems from the fact that Android OS is written for ARM processor (not for Intel/AMD processor or let’s say not for computer processor). Therefore when we get our apps run on Android emulator (which is running on Intel/AMD processor), every assembly code row has to be emulated. A run-time binary translation will happen to translate every assembly code of development machine to device machine. And that point slows down everything.
Flickr is a wonderful image hosting and video hosting of Yahoo. With a free account, you can get a disk space up to 1 TB for uploading and sharing your photos as well as videos. In this post, I would like to make a small demo showing how we can consume the Flickr’s REST web service and display public images of an album on Android phone. The images could be shown either in thumbnail mode or medium mode. The example app is just a proof of concept, you have to improve it when you want to build a same one in practice because I just don’t care about optimizing resources (memory) in source code. You will also ‘learn’ how to implement a singleton pattern (in entire app) with roboguice. That means, small example, interesting use cases.
Tab control is a popular component in desktop application. I think, most of desktop application contains at least a tab control in one way or another. In Android environment, we also have a tab control named “TabHost”, but since Android 3.0, it was replaced by ActionBar. In this post I would like to show how we can make a “fake” tab layout with ActionBar so that we can give user the same experience like TabHost. This control is built up by a combination of ActionBar and FragmentPagerAdapter. The labels will be located at the top, switching between tabs will load the content of the tabs. Moreover thanks to touch screen of smartphone, user can also swipe to navigate between tabs. The final result of our “fake” tab layout looks like following image (Please note that we aren’t going to make a “tab control” but a “tab layout”, they are different concepts)